Flutter WebView html select无法打开

Question

我通过更改一些代码行和3次导入设法解决了应用程序崩溃的问题。

现在我的FlutterWebView看起来像这样：

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package io.flutter.plugins.webviewflutter;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.ContextWrapper;
import android.hardware.display.DisplayManager;
import android.os.Build;
import android.os.Handler;
import android.view.View;
import android.app.Activity;
import android.webkit.WebStorage;
import android.webkit.WebViewClient;
import io.flutter.app.FlutterApplication;
import io.flutter.plugin.common.BinaryMessenger;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;
import io.flutter.plugin.platform.PlatformView;
import java.util.Collections;
import java.util.List;
import java.util.Map;

public class FlutterWebView implements PlatformView, MethodCallHandler {
  private static final String JS_CHANNEL_NAMES_FIELD = "javascriptChannelNames";
  private final InputAwareWebView webView;
  private final MethodChannel methodChannel;
  private final FlutterWebViewClient flutterWebViewClient;
  private final Handler platformThreadHandler;

  @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
  @SuppressWarnings("unchecked")
  FlutterWebView(
      final Context context,
      BinaryMessenger messenger,
      int id,
      Map<String, Object> params,
      View containerView) {

    Context wrappedContext = wrapContext(context);
    Context appContext = context.getApplicationContext();
    DisplayListenerProxy displayListenerProxy = new DisplayListenerProxy();
    DisplayManager displayManager =
        (DisplayManager) wrappedContext.getSystemService(Context.DISPLAY_SERVICE);
    displayListenerProxy.onPreWebViewInitialization(displayManager);
    if (appContext != null) {
      wrappedContext = appContext;
    }
    webView = new InputAwareWebView(wrappedContext, containerView);
    displayListenerProxy.onPostWebViewInitialization(displayManager);

    platformThreadHandler = new Handler(wrappedContext.getMainLooper());
    // Allow local storage.
    webView.getSettings().setDomStorageEnabled(true);

    methodChannel = new MethodChannel(messenger, "plugins.flutter.io/webview_" + id);
    methodChannel.setMethodCallHandler(this);

    flutterWebViewClient = new FlutterWebViewClient(methodChannel);
    applySettings((Map<String, Object>) params.get("settings"));

    if (params.containsKey(JS_CHANNEL_NAMES_FIELD)) {
      registerJavaScriptChannelNames((List<String>) params.get(JS_CHANNEL_NAMES_FIELD));
    }

    updateAutoMediaPlaybackPolicy((Integer) params.get("autoMediaPlaybackPolicy"));
    if (params.containsKey("userAgent")) {
      String userAgent = (String) params.get("userAgent");
      updateUserAgent(userAgent);
    }
    if (params.containsKey("initialUrl")) {
      String url = (String) params.get("initialUrl");
      webView.loadUrl(url);
    }
  }

  private Context wrapContext(Context context) {
    Context activityContext = context;
    Context appContext = context.getApplicationContext();
    if (appContext instanceof FlutterApplication) {
      Activity currentActivity = ((FlutterApplication) appContext).getCurrentActivity();
      if (currentActivity != null) {
        activityContext = currentActivity;
      }
    }
    final Context finalContext = activityContext;
    // Cannot use activityContext, which will cause the keyboard to be unable to input.
    // We have to wrap the original context.
    return new ContextWrapper(context) {
      @Override
      public Object getSystemService(String name) {
        if (name == Context.WINDOW_SERVICE) {
          return finalContext.getSystemService(name);
        }
        return super.getSystemService(name);
      }
    };
  }

  @Override
  public View getView() {
    return webView;
  }

  // @Override
  // This is overriding a method that hasn't rolled into stable Flutter yet. Including the
  // annotation would cause compile time failures in versions of Flutter too old to include the new
  // method. However leaving it raw like this means that the method will be ignored in old versions
  // of Flutter but used as an override anyway wherever it's actually defined.
  // TODO(mklim): Add the @Override annotation once flutter/engine#9727 rolls to stable.
  public void onInputConnectionUnlocked() {
    webView.unlockInputConnection();
  }

  // @Override
  // This is overriding a method that hasn't rolled into stable Flutter yet. Including the
  // annotation would cause compile time failures in versions of Flutter too old to include the new
  // method. However leaving it raw like this means that the method will be ignored in old versions
  // of Flutter but used as an override anyway wherever it's actually defined.
  // TODO(mklim): Add the @Override annotation once flutter/engine#9727 rolls to stable.
  public void onInputConnectionLocked() {
    webView.lockInputConnection();
  }

  // @Override
  // This is overriding a method that hasn't rolled into stable Flutter yet. Including the
  // annotation would cause compile time failures in versions of Flutter too old to include the new
  // method. However leaving it raw like this means that the method will be ignored in old versions
  // of Flutter but used as an override anyway wherever it's actually defined.
  // TODO(mklim): Add the @Override annotation once stable passes v1.10.9.
  public void onFlutterViewAttached(View flutterView) {
    webView.setContainerView(flutterView);
  }

  // @Override
  // This is overriding a method that hasn't rolled into stable Flutter yet. Including the
  // annotation would cause compile time failures in versions of Flutter too old to include the new
  // method. However leaving it raw like this means that the method will be ignored in old versions
  // of Flutter but used as an override anyway wherever it's actually defined.
  // TODO(mklim): Add the @Override annotation once stable passes v1.10.9.
  public void onFlutterViewDetached() {
    webView.setContainerView(null);
  }

  @Override
  public void onMethodCall(MethodCall methodCall, Result result) {
    switch (methodCall.method) {
      case "loadUrl":
        loadUrl(methodCall, result);
        break;
      case "updateSettings":
        updateSettings(methodCall, result);
        break;
      case "canGoBack":
        canGoBack(result);
        break;
      case "canGoForward":
        canGoForward(result);
        break;
      case "goBack":
        goBack(result);
        break;
      case "goForward":
        goForward(result);
        break;
      case "reload":
        reload(result);
        break;
      case "currentUrl":
        currentUrl(result);
        break;
      case "evaluateJavascript":
        evaluateJavaScript(methodCall, result);
        break;
      case "addJavascriptChannels":
        addJavaScriptChannels(methodCall, result);
        break;
      case "removeJavascriptChannels":
        removeJavaScriptChannels(methodCall, result);
        break;
      case "clearCache":
        clearCache(result);
        break;
      case "getTitle":
        getTitle(result);
        break;
      default:
        result.notImplemented();
    }
  }

  @SuppressWarnings("unchecked")
  private void loadUrl(MethodCall methodCall, Result result) {
    Map<String, Object> request = (Map<String, Object>) methodCall.arguments;
    String url = (String) request.get("url");
    Map<String, String> headers = (Map<String, String>) request.get("headers");
    if (headers == null) {
      headers = Collections.emptyMap();
    }
    webView.loadUrl(url, headers);
    result.success(null);
  }

  private void canGoBack(Result result) {
    result.success(webView.canGoBack());
  }

  private void canGoForward(Result result) {
    result.success(webView.canGoForward());
  }

  private void goBack(Result result) {
    if (webView.canGoBack()) {
      webView.goBack();
    }
    result.success(null);
  }

  private void goForward(Result result) {
    if (webView.canGoForward()) {
      webView.goForward();
    }
    result.success(null);
  }

  private void reload(Result result) {
    webView.reload();
    result.success(null);
  }

  private void currentUrl(Result result) {
    result.success(webView.getUrl());
  }

  @SuppressWarnings("unchecked")
  private void updateSettings(MethodCall methodCall, Result result) {
    applySettings((Map<String, Object>) methodCall.arguments);
    result.success(null);
  }

  @TargetApi(Build.VERSION_CODES.KITKAT)
  private void evaluateJavaScript(MethodCall methodCall, final Result result) {
    String jsString = (String) methodCall.arguments;
    if (jsString == null) {
      throw new UnsupportedOperationException("JavaScript string cannot be null");
    }
    webView.evaluateJavascript(
        jsString,
        new android.webkit.ValueCallback<String>() {
          @Override
          public void onReceiveValue(String value) {
            result.success(value);
          }
        });
  }

  @SuppressWarnings("unchecked")
  private void addJavaScriptChannels(MethodCall methodCall, Result result) {
    List<String> channelNames = (List<String>) methodCall.arguments;
    registerJavaScriptChannelNames(channelNames);
    result.success(null);
  }

  @SuppressWarnings("unchecked")
  private void removeJavaScriptChannels(MethodCall methodCall, Result result) {
    List<String> channelNames = (List<String>) methodCall.arguments;
    for (String channelName : channelNames) {
      webView.removeJavascriptInterface(channelName);
    }
    result.success(null);
  }

  private void clearCache(Result result) {
    webView.clearCache(true);
    WebStorage.getInstance().deleteAllData();
    result.success(null);
  }

  private void getTitle(Result result) {
    result.success(webView.getTitle());
  }

  private void applySettings(Map<String, Object> settings) {
    for (String key : settings.keySet()) {
      switch (key) {
        case "jsMode":
          updateJsMode((Integer) settings.get(key));
          break;
        case "hasNavigationDelegate":
          final boolean hasNavigationDelegate = (boolean) settings.get(key);

          final WebViewClient webViewClient =
              flutterWebViewClient.createWebViewClient(hasNavigationDelegate);

          webView.setWebViewClient(webViewClient);
          break;
        case "debuggingEnabled":
          final boolean debuggingEnabled = (boolean) settings.get(key);

          webView.setWebContentsDebuggingEnabled(debuggingEnabled);
          break;
        case "userAgent":
          updateUserAgent((String) settings.get(key));
          break;
        default:
          throw new IllegalArgumentException("Unknown WebView setting: " + key);
      }
    }
  }

  private void updateJsMode(int mode) {
    switch (mode) {
      case 0: // disabled
        webView.getSettings().setJavaScriptEnabled(false);
        break;
      case 1: // unrestricted
        webView.getSettings().setJavaScriptEnabled(true);
        break;
      default:
        throw new IllegalArgumentException("Trying to set unknown JavaScript mode: " + mode);
    }
  }

  private void updateAutoMediaPlaybackPolicy(int mode) {
    // This is the index of the AutoMediaPlaybackPolicy enum, index 1 is always_allow, for all
    // other values we require a user gesture.
    boolean requireUserGesture = mode != 1;
    webView.getSettings().setMediaPlaybackRequiresUserGesture(requireUserGesture);
  }

  private void registerJavaScriptChannelNames(List<String> channelNames) {
    for (String channelName : channelNames) {
      webView.addJavascriptInterface(
          new JavaScriptChannel(methodChannel, channelName, platformThreadHandler), channelName);
    }
  }

  private void updateUserAgent(String userAgent) {
    webView.getSettings().setUserAgentString(userAgent);
  }

  @Override
  public void dispose() {
    methodChannel.setMethodCallHandler(null);
    webView.dispose();
    webView.destroy();
  }
}

现在，当我尝试打开此选择时：

我使用cortexpower.de网站

我从Android Studio的Logcat中收到以下错误：

2019-12-16 15:55:16.338 32604-32627/com.example.newapp E/AwareLog: AtomicFileUtils: readFileLines file not exist: android.util.AtomicFile@b76c34c
2019-12-16 15:55:16.343 32604-32622/com.example.newapp E/MemoryLeakMonitorManager: MemoryLeakMonitor.jar is not exist!
2019-12-16 15:55:23.549 32604-32604/com.example.newapp A/chromium: [FATAL:jni_android.cc(249)] Please include Java exception stack in crash report
2019-12-16 15:55:23.550 32604-32604/com.example.newapp A/libc: Fatal signal 5 (SIGTRAP), code 1 (TRAP_BRKPT), fault addr 0x76b69143e8 in tid 32604 (.example.newapp), pid 32604 (.example.newapp)

在创建新应用时，我必须设置一个名称和网站。多数民众赞成在这个奇怪的链接在错误。我不知道这是否引起水灾。

感谢您的帮助！